Rene boon



UNITED STATES PATENT OFFICE RENE l'iOllN, Oli l UDV'IGSllAFEN-ON HE-RUIN l, BAY'ARIA, ASSIGNOR TO THE BADTSUHE ANllilN AND SODA FABRTK, (3F )LXNNTIEIM, GERMANY.

ALIZARINE-BLUE SU LPHURIC ACID.

SPECIFICATION forming part of Letters Patent No. 399,481, dated March 12, 1889.

Application filed October 18, 1888. Serial No. 288,432. (Specimens To all who/1t it may canoe/'21 the application of the known n1eth nls*forin- Be it known that I, RENE BOHN, a citizen of stance, by mixing the free alizarine-blue sul- Switzerland,residing at Ludwigshaten-on-thephuric acid obtained as above described in Rhine, in the Kingdom of Bavaria and Emthe state of a pressed pulp with as much of a pire of Germany, have invented new and usediluted caustic-soda liquor as will be required ful Improvements in the Manufacture of Alizfor converting the same into a purple crysarine-Blue Sulphuric Acid, of which the foltalline salt, presenting the appearance of pure lowing is a specification. indigotine. The sodium salt of the coloring- My invention relates to the man uii'acture of matter thus prepared may then be obtained 10 an improved dye-stuff or coloring-matter proin a dry state by evaporation. I duced by the limited or moderate action of Alizarine-blue sulphuric acid produced as sulphuric anhydridc upon alizarine-blue. above described presents the following char- My improved d ye-stu ii. or coloring-matter is acteristic properties: It is capable of forming termed alizarinc-blue sulphuric acid, in ortwo series of alkaline salts soluble in water.

I5 der to indicate by this name both its origin Those containing the minimum of alkali exand its chiefly available property of splitting hibit a yellow or brown appearance both in upinto alizarine-blue and sulphuric acid when the dry state and in the state of their concensubmitted to the influence of acids or acid trated aqueous solutions, while a larger promordants in the processes of dyeing or printportion of alkali effects a change of the said 20 g. colors into purple or blue. The purple solu- In carrying out my invention I proceed as tion of the potassium or sodium salts assumes :l llows: About ten parts, by weight, of dry gradually the before-named yellow or brown and finely-powdored alizarineblue are, in tint upon the addition of water. A similar a small portions at a time and under constant change (owing to an abstraction of alkali) 25 stirring, added to about twenty parts, by takes place by carefully adding a small weight, of fuming sulphuric acid containing amount of a mineral or organic acid or by about twenty-three per cent. of free anhydride. passing a current-of carbonic acid into the said This operation,which requires about from four purple solutions. This point being reached, to six hours, being finished, the mixture or a furtheraddition of a mineral or organic acid 0 solution thus obtained is to be kept agitated causes the alizarine-blue sulphuric acid thus So at a temperature of about 50 cen ti gradedurset free to become precipitated in alizarineing the spaeeo'l about from four to fivehours, like yellow flocks, which (prickly assume a in order to insure a perfect (liSSOllliilOll of the crystalline appearance. ly the simultaneous alizarinc-blue, and then the conversion of the ap ilication of heat the almve-named decom- 3 5 latter into its SlllplHll'lC- Wld derivative is to position ensues, alizarine-blue and sulphuric be completed by continuously agitating the acid being the result. This decomposition solution at an ordinary temperature during forms an especially striking experiment if f about another twelve hours. Throughout this acetic acid be employed for such purpose, the

operation the access of moist air ought to be solution becomingdecolorizechwhile alizarine- 4o carefully excluded. The result of the problue separates out in small glittering crystals cess is then gradually poured int-o a mixture closely resemljiling artificial indigo. By emot ice and water, and the prcci 'iiiate of alizploying sulphuric or hydrochloric acids in ariuc-blue sul huric acid thus produced -is to sufficient excess the well-known red solutions be filtered as quickly as possible, washed with of the corres 'iomling salts of aliZarine-blue 45 ice-cold water, and pressed. will be observed to form. The alkaline solu- In order to convert the free and unstable tions of ZtllZiLllllG-blllfi sulphuric acid are prealizarine-blue sulphuric acid into a commercipitated by caustic and carbonated alkalies cial product soluble in water and possessing as well asbycommon salt. Alkaline-reducing a suflicient degree of stability, it is advisable agentssuch, for instance, as zinc-dust and 50 to prepare the alkaline salts of the same by caustic-potash liquor-cause the purple color of the alkaline solutions of alizarine-blue sulphuric acid. to change into a yellow tint, which, upon the access of air, changes back into the original purple hue. Al izarine-blue sulphuric acid is chiefly useful. for dyeing WOOl or other animal fiber with the aid of mordants used for the production of the variously-colored lakes of alizarine-blue. On account of sulphuric acid becoming liberated during its deseries of alkaline salts, those containing the minimum of alkali. exhibiting a yellow or brown appearance, while a larger proportion of alkali e'lfects a change of the said color into purple or blue; by adding to the purple solution a small amount of mineral ororganic acid it assumes gradually the before-named yellow or brown tint; by the further addition of a mineral or organic acid the alizarlne-blue sulphuric acid becomes meeipitatedin alizarinelike yellow flocks, and it dyes wool or other animal fiber with the aid of mordai'its blue.

In testimony whereof I have hereunto set my hand in the presence of two subscribing- Witnesses.

REJ'E BOHN. Witnesses:

AUGUST HANSE, J OHANNES BiiTTNER.

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